1. Field of the Invention
The present invention relates generally to generating signals in networking systems. More particularly, embodiments of the invention relate generally to generating clock signals for testing high speed data transmission systems and components.
2. Background Technology
Computer and data communications networks continue to proliferate due to declining costs, increasing performance of computer and networking equipment, and increasing demand for communication bandwidth. As the demand for networks has grown, network technology has developed to the point that many different physical configurations presently exist. Examples include Gigabit Ethernet (“GE”), 10 GE, Fiber Distributed Data Interface (“FDDI”), Fibre Channel (“FC”), Synchronous Optical Network (“SONET”) and InfiniBand networks. These networks, and others, typically conform to one of a variety of established standards, or protocols, which set forth rules that govern network access as well as communications between and among the network resources. Typically, such networks utilize different cabling systems, have different characteristic bandwidths and typically transmit data at different speeds.
Each protocol typically supports various data rates or transmission speeds. With each increase in a data rate, a protocol typically will support the new data rate, while continuing to support the slower, prior data rates. This permits networks to support a variety of components operating at a variety of data rates. Not only do data rates differ within a protocol, but different protocols often provide different data rates. Accordingly, a network may include a variety of protocols that may each support a variety of data rates.
To provide a clock signal for a diagnostic system that supports these data rates, a conventional approach is to include a large number of oscillators that provide a large number of needed frequencies. As the number of oscillators increases, noise in the network increases. The resulting noise can have an adverse effect on the network itself as well as the ability of diagnostic equipment to test and monitor the network.